EXTJS How to upload image to hsql database from extjs client side in json object

I have image upload field like

{
     xtype: 'textfield',  
     fieldLabel: 'Image',  
     labelSeparator: '',  
     name: 'newPic',  
     id:'newPic',  
     anchor:'100%',  
     inputType: 'file',  
     allowBlank: false  
 }
 

When i submitting form, Im encoding all form data in a json object.All textfields data are coming in json object but not image is passing to server side . How to pass image so as to save it in server side

var form=Ext.getCmp('empPersonal');
 var formdata=Ext.JSON.encode(form.getValues());
 alert(""+formdata);
 if(Ext.getCmp('empPersonal').getForm().isValid()) {
     Ext.Ajax.request({ 
     url:'ws/employees/create/'+formdata,
 

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